Question

multiple-choice questions

1. stellas respiratory system is not working well. why is this a problem for her ability to exercise?

a her respiratory system will not be able to break down molecules from air into oxygen.
b her cells will not work well when they have low levels of oxygen.
c her digestive system will have to work twice as hard to get the same amount of energy from glucose molecules.
d her cells will not work because molecules from air will be too large for her body to use.

Explanation:

The respiratory system's main function is to supply oxygen to the body. During exercise, cells need more oxygen for cellular respiration (to produce energy). If the respiratory system isn't working well, oxygen supply is limited. Cells rely on oxygen for efficient energy production (aerobic respiration). Without enough oxygen, cells can't function optimally during exercise. Option a is wrong because the respiratory system doesn't break down molecules into oxygen (air already has oxygen). Option c is about the digestive system which is not directly related to the respiratory system's role in oxygen supply. Option d is incorrect as air molecules (like oxygen) are not too large for the body to use.

Answer:

B. Her cells will not work well when they have low levels of oxygen.